E-cadherin: gatekeeper of airway mucosa and allergic sensitization. Trends Immunol. 2011;32:248-255. [PMID: 21493142 DOI: 10.1016/j.it.2011.03.004]

Weakened Airway Epithelial Junctions and Enhanced Neutrophil Elastase Release Contribute to Age-Dependent Bacteremia Risk Following Pneumococcal Pneumonia

Streptococcus pneumoniae (Sp; pneumococcus), the most common agent of community-acquired pneumonia, can spread systemically, particularly in the elderly, highlighting the need for adjunctive therapies. The airway epithelial barrier defends against bacteremia and is dependent upon apical junctional complex (AJC) proteins such as E-cadherin. After mouse lung challenge, pneumolysin (PLY), a key Sp virulence factor, stimulates epithelial secretion of an inflammatory eicosanoid, triggering the infiltration of polymorphonuclear leukocytes (PMNs) that secrete high levels of neutrophil elastase (NE), thus promoting epithelial damage and systemic infection. Here, pulmonary E-cadherin staining of intratracheally (i.t.) inoculated mice revealed PLY-mediated disruption of AJC independently of PMNs. Apical infection of air-liquid interface (ALI) respiratory epithelial monolayers similarly showed that PLY disrupts AJCs. This epithelial damage promoted PMN transmigration and bacterial apical-to-basolateral translocation, and pharmacologically fortifying epithelial barrier function diminished both barrier breach in vitro and bacteremia in vivo. E-cadherin staining after Sp i.t. inoculation of > 20-month-old mice, or apical infection of ALI monolayers derived from these mice, revealed an age-associated vulnerability to PLY-mediated AJC disruption, which in turn enhanced PMN migration and bacteremia. In addition, we found that PMNs from aged mice secrete increased levels of tissue-damaging NE. Simultaneous pharmacological inhibition of tissue-destructive NE and fortification of pulmonary epithelial barrier function was required to reduce the level of Sp bacteremia in aged mice to that of young mice. This work underscores the importance of fully characterizing the multifactorial sources of age-associated susceptibility in devising adjunctive therapies to mitigate invasive pneumococcal disease in the elderly.

GLUT1 mediates bronchial epithelial E-cadherin disruption in TDI-induced steroid-insensitive asthma

OBJECTIVE

Down-regulation of bronchial epithelial E-cadherin is an important of feature of severe asthma, including steroid-insensitive asthma. Yet, the mechanisms involved in E-cadherin disruption are not fully understood. This study was aimed to investigate the role of glucose transporter 1 (GLUT1) in dysregulation of E-cadherin in toluene diisocyanate (TDI)-induced steroid-insensitive asthma.

METHODS

A murine model of steroid-insensitive asthma was established by TDI sensitization and aerosol inhalation. Selective GLUT1 antagonists WZB117 and BAY876 were given to BALB/c mice after airway challenge. In vitro, primary human bronchial epithelial cells (HBECs) cultured in an airway-liquid interface (ALI) were exposed to TDI.

RESULTS

TDI exposure markedly up-regulated GLUT1 in murine lungs and HBECs. Pharmacological inhibition of GLUT1 with BAY876 decreased airway hyperresponsiveness, neutrophil and eosinophil accumulation, as well as type 2 inflammation in vivo. Besides, the TDI-induced down-regulated expression of full-length E-cadherin was also partly recovered, accompanied by inhibited secretion of soluble E-cadherin (sE-cadherin). WZB117 also exhibited mild therapeutic effects, though not significant. In vitro, treatment with GLUT1 inhibitor relieved the TDI-induced disruption of E-cadherin in HBECs.

CONCLUSIONS

Taken together, our data demonstrated that GLUT1 modulates bronchial epithelial E-cadherin dysfunction production in TDI-induced steroid-insensitive asthma.

TRPV4 Mediates Alveolar Epithelial Barrier Integrity and Induces ADAM10-Driven E-Cadherin Shedding

Transient receptor potential vanilloid 4 (TRPV4) channels have been associated with numerous pulmonary pathologies, including hypertension, asthma, and acute lung injury. However, their role in the alveolar epithelium remains unclear. We performed impedance-based resistance measurements in primary differentiated alveolar epithelial type I (AT1) cells from wild-type (WT) and TRPV4-deficient (TRPV4-/-) C57/BL6J mice to detect changes in AT1 barrier integrity upon TRPV4 activation. Both pharmacological (GSK1016790A) and a low pH-driven activation of TRPV4 were quantified, and the downstream effects on adherens junctions were assessed through the Western blotting of epithelial cadherin (E-cadherin) protein levels. Importantly, a drop in pH caused a rapid decrease in AT1 barrier resistance and increased the formation of a ~35 kDa E-cadherin C-terminal fragment, with both effects significantly reduced in TRPV4-/- AT1 cells. Similarly, the pharmacological activation of TRPV4 in AT1 cells triggered an immediate transient loss of barrier resistance and the formation of the same E-cadherin fragment, which was again diminished by TRPV4 deficiency. Moreover, TRPV4-mediated E-cadherin cleavage was significantly reduced by GI254023X, an antagonist of a disintegrin and metalloprotease 10 (ADAM10). Our results confirm the role of TRPV4 in regulating alveolar epithelial barrier permeability and provide insight into a novel signaling pathway by which TRPV4-induced Ca2+ influx stimulates metalloprotease-driven ectodomain shedding.

The therapeutic effect of Yinqiaosan decoction against influenza A virus infection by regulating T cell receptor signaling pathway

Background

Yinqiaosan decoction (YQSD), a traditional Chinese medicinal recipe, has been employed to treat influenza in China for approximately 300 years.

Objective

Our study aimed to explore the mechanisms of YQSD against influenza via in vivo and in vitro experimental studies.

Study design

and methods UHPLC-Q-TOF-MS/MS was utilized to examine the substances of the YQSD. The chemical components of YQSD detected by UHPLC-Q-TOF-MS/MS were used for network pharmacology analysis. The antiviral effect of YQSD in vivo was investigated. The potential mechanisms of YQSD in combating influenza, which were predicted from network pharmacology analysis, were validated in vitro.

Results

By use of UHPLC-Q-TOF-MS/MS, 97 compounds were identified from YQSD. Network pharmacology analysis revealed that the therapeutic effect of YQSD against influenza may be associated with the regulation of T cell receptors (TCR) and Phosphoinositide 3-Kinase (PI3K)- protein kinase B (Akt) signaling pathways. Treatment with YQSD significantly prolonged the mean survival time of the mice and reduced lung injury due to the influenza A virus in vivo. It was discovered that YQSD efficiently inhibited the expression of inflammation-related cytokines. Moreover, YQSD has been found to significantly reduce the expression levels of cluster of differentiation 3 (CD3), monocyte chemoattractant protein-1 (MCP-1), and H1N1 virus nucleoprotein (NP), and prevent the decrease of epithelial cadherin (E-cadherin) protein. In addition, YQSD can inhibit the phosphorylation of the zeta chain of T cell receptor-associated protein kinase 70 (ZAP70) and PI3K proteins in vitro.

Conclusion

The capacity of YQSD to suppress viral multiplication and inflammatory response by modulating T cell immunity may explain its effect against influenza viral pneumonia, which may involve the regulation of TCR and PI3K signaling pathways.

Chemical respiratory sensitization-Current status of mechanistic understanding, knowledge gaps and possible identification methods of sensitizers

Respiratory sensitization is a complex immunological process eventually leading to hypersensitivity following re-exposure to the chemical. A frequent consequence is occupational asthma, which may occur after long latency periods. Although chemical-induced respiratory hypersensitivity has been known for decades, there are currently no comprehensive and validated approaches available for the prospective identification of chemicals that induce respiratory sensitization, while the expectations of new approach methodologies (NAMs) are high. A great hope is that due to a better understanding of the molecular key events, new methods can be developed now. However, this is a big challenge due to the different chemical classes to which respiratory sensitizers belong, as well as because of the complexity of the response and the late manifestation of symptoms. In this review article, the current information on respiratory sensitization related processes is summarized by introducing it in the available adverse outcome pathway (AOP) concept. Potentially useful models for prediction are discussed. Knowledge gaps and gaps of regulatory concern are identified.

Ferroptosis contributes to airway epithelial E-cadherin disruption in a mixed granulocytic asthma mouse model

Aberrant expression of airway epithelial E-cadherin is a key feature of asthma, yet the underlying mechanisms are largely unknown. Ferroptosis is a novel form of regulated cell death involved in asthma pathogenesis. This study was aimed to evaluate the role of ferroptosis and to investigate whether ferroptosis mediates E-cadherin disruption in mixed granulocyte asthma (MGA). Two murine models of MGA were established using toluene diisocyanate (TDI) or ovalbumin with Complete Freund's Adjuvant (OVA/CFA). Specific antagonists of ferroptosis, including Liproxstatin-1 (Lip-1) and Ferrostatin-1 (Fer-1) were given to the mice. The allergen-exposed mice displayed markedly shrunk mitochondria in the airway epithelia, with decreased volume and denser staining accompanied by down-regulated GPX4 as well as up-regulated FTH1 and malondialdehyde, which are markers of ferroptosis. Decreased pulmonary expression of E-cadherin was also observed, with profound loss of membrane E-cadherin in the airway epithelia, as well as increased secretion of sE-cadherin. Treatment with Lip-1 not only showed potent protective effects against the allergen-induced airway hyperresponsiveness and inflammatory responses, but also rescued airway epithelial E-cadherin expression and inhibited the release of sE-cadherin. Taken together, our data demonstrated that ferroptosis mediates airway epithelial E-cadherin dysfunction in MGA.

The airway epithelium: an orchestrator of inflammation, a key structural barrier and a therapeutic target in severe asthma

Asthma is a disease of heterogeneous pathology, typically characterised by excessive inflammatory and bronchoconstrictor responses to the environment. The clinical expression of the disease is a consequence of the interaction between environmental factors and host factors over time, including genetic susceptibility, immune dysregulation and airway remodelling. As a critical interface between the host and the environment, the airway epithelium plays an important role in maintaining homeostasis in the face of environmental challenges. Disruption of epithelial integrity is a key factor contributing to multiple processes underlying asthma pathology. In this review, we first discuss the unmet need in asthma management and provide an overview of the structure and function of the airway epithelium. We then focus on key pathophysiological changes that occur in the airway epithelium, including epithelial barrier disruption, immune hyperreactivity, remodelling, mucus hypersecretion and mucus plugging, highlighting how these processes manifest clinically and how they might be targeted by current and novel therapeutics.

Tectorigenin inhibits oxidative stress by activating the Keap1/Nrf2/HO-1 signaling pathway in Th2-mediated allergic asthmatic mice

Asthma is a chronic obstructive airway condition and one of the most common non-communicable illnesses worldwide. Tectorigenin (Tec) is an isoflavonoid found in plants that possesses significant antioxidative and anti-inflammatory abilities. Nevertheless, the antioxidative properties of Tec have not yet been documented in allergic asthma. In this study, we created an asthmatic BALB/c mouse model induced by ovalbumin (OVA) and used it to assess the efficacy of Tec as a possible therapy agent. Tec decreased the serum OVA-specific immunoglobulin (Ig) E and IgG1 secretion levels. The total number of cells and the distribution of inflammatory cells decreased significantly in bronchoalveolar lavage fluid (BALF), with weakened inflammatory reaction in pulmonary tissues. Additionally, Tec regulated the T helper 1(Th1)/Th2 balance by increasing the expression of Th1- related factors (interleukin (IL)-12 and T-bet) and decreasing the expression of Th2-related factors (IL-4, IL-5, IL-13, and GATA binding protein 3. In addition, the pro-inflammatory cytokines such as IL-6, tumor necrosis factor-alpha, and IL-1β were also inhibited by Tec. Tec also dramatically increased antioxidant (catalase and superoxide dismutase) concentrations while lowering the intensity of the indicators of oxidative stress such as reactive oxygen species and malondialdehyde in BALF. Finally, Tec effectively activated the Keap1/Nrf2/HO-1 signaling pathway and prevented the epithelial-mesenchymal transition. The results of the current study show that Tec may be useful in relieving the inflammatory and oxidative stress responses associated with asthma.

Robust and self-lubricating polyvinyl alcohol tubes with a mucosa-like hierarchical architecture for endotracheal intubation

Mechanical mismatch between interventional intubation tubes and human tissues often triggers inevitable friction and causes secondary injury to patients during interventional therapy. Herein, we propose a fabrication strategy of a self-lubricating polyvinyl alcohol (PVA) tube by industrial extrusion technology followed by simple infiltration with water. First, biocompatible glycerin was introduced to weaken the intrinsic hydrogen interaction of PVA by new molecular complexation, broadening the gap between the melting and decomposition temperatures and enabling the stable extrusion of the PVA tube. Subsequently, the as-prepared PVA tube was infiltrated with an aqueous solution to construct a strong hydrogen bonding network between PVA and water molecules, forming a soft hydration layer similar to the upper epithelium layer of mucosa. Benefiting from the solid and liquid properties of the hydration layer as well as the small proportion relative to the whole, the infiltrated PVA tube exhibited excellent hydration lubrication behavior and robust mechanical property. The friction coefficient, tensile strength and elongation at break were measured to be 0.05, 26.2 MPa and 654%, respectively, surpassing the values of 0.5, 16.4 MPa and 240% observed in a commercial polyvinyl chloride tube. In vitro, the PVA intubation tube demonstrated significant biocompatibility, and short-term exposure exhibited minimal impacts on the morphology and proliferation of L929 cells. Ultimately, the potential of the infiltrated PVA tube for interventional intubation was demonstrated successfully using an in vivo rabbit model, providing a new idea for the follow-up development of interventional intubation tubes.

Potential Proallergenic Activity of Phytopathogenic Erysiphe palczewskii and Erysiphe convolvuli in in vitro Studies

Purpose

Allergic diseases have reached epidemic proportions globally, affecting nearly 30% of the world's population. One of the most prominent sources of allergens is fungi, causing up to 6% of respiratory diseases in the general population. However, the cause of respiratory allergies is not always identifiable. Therefore, we studied the ability of two representatives of common powdery mildew (Erysiphales), Erysiphe palczewskii and Erysiphe convolvuli, to induce a proinflammatory response in in vitro models of the upper and lower respiratory tract.

Materials and Methods

Two cell lines, BEAS-2B and A549, were used to mimic upper and lower respiratory epithelial cells. The toxicity of fungal extracts was assessed with MTT and flow cytometry assay. The production of reactive oxygen species in the cells was measured with flow cytometry. ELISA tests were used to determine the production of proinflammatory cytokines. The presence of the cell integrity marker was assessed with the immunofluorescence method.

Results

In both cell lines, the extract of E. palczewskii and E. convolvuli microfungi induced marked production of proinflammatory IL-1β, TNF-α, and GM-CSF cytokines involved in developing allergic reactions. The higher levels of these cytokines with higher reactive oxygen species synthesis positively correlated with the disruption of epithelial cell junctions.

Conclusion

We conclude that E. palczewskii and E. convolvuli microfungi have strong proinflammatory and proallergenic potential, but this finding needs in vivo confirmation.

The contribution of reticular basement membrane proteins to basal airway epithelial attachment, spreading and barrier formation: implications for airway remodeling in asthma

Rationale

In the healthy lung, the pseudostratified conducting airway epithelium is anchored to the reticular basement membrane (RBM) via hemidesmosome junction complexes formed between basal cells and the extracellular matrix (ECM). The RBM within the healthy lung is composed of the ECM proteins laminin and collagen-IV. In patients with asthma, the RBM is remodeled with collagen-I, -III and fibronectin deposition. The goal of this study was to assess the effect of RBM ECM proteins on basal airway epithelial cell attachment, spreading and barrier formation using real-time electrical cell-substrate impedance sensing (ECIS).

Methods

ECIS 8-well arrays were coated with 50 μg/mL of fibronectin, collagen-I, collagen-III, collagen-IV, or laminin and compared to bovine serum albumin (BSA) or uncoated controls. The airway epithelial cell line (1HAEo-) was seeded 40, 50, 60, and 70 k cells/well and continuously monitored over 70 h to assess cell attachment, spreading and barrier formation using high (64 k Hz) and low (500 Hz) frequency resistance and capacitance. Data were analyzed using a one-phase decay model from which half-life (time cells cover half of the electrode area) and rate-constant (cell-spreading rate/h) were determined and a generalized additive mixed effect model (GAMM) was used to assess ECM proteins over the entire experiment.

Results

High-frequency (64 kHz) capacitance measures demonstrated the half-life for 1HAEo-cells to attach was fastest when grown on fibronectin (6.5 h), followed by collagen-I (7.2 h) and collagen-III (8.1 h), compared to collagen-IV (11.3 h), then laminin (13.2 h) compared to BSA (12.4 h) and uncoated (13.9 h) controls. High-frequency (64 kHz) resistance measures demonstrated that the rate of 1HAEo- cell spreading was significantly faster on fibronectin and collagen-I compared to collagen-III, collagen-IV, laminin, BSA and the uncoated control. Low-frequency (500 Hz) resistance measures demonstrated that 1HAEo-cells formed a functional barrier fastest when grown on fibronectin and collagen-I, compared to the other ECM conditions. Lastly, the distance of 1HAEo-cells from the ECM substrates was the smallest when grown on fibronectin reflecting high cell-matrix adhesion.

Conclusion

Airway epithelial cells attach, spread and form a barrier fastest on fibronectin, and collagen-I and these reticular basement membrane ECM proteins may play a protective role in preserving the epithelial barrier during airway remodeling in asthma.

Macrophage migration inhibitory factor exacerbates asthmatic airway remodeling via dynamin-related protein 1-mediated autophagy activation

BACKGROUND

Macrophage migration inhibitory factor (MIF) and GTPase dynamin-related protein 1 (Drp1)-dependent aberrant mitochondrial fission are closely linked to the pathogenesis of asthma. However, it is unclear whether Drp1-mediated mitochondrial fission and its downstream targets mediate MIF-induced proliferation of airway smooth muscle cells (ASMCs) in vitro and airway remodeling in chronic asthma models. The present study aims to clarify these issues.

METHODS

In this study, primary cultured ASMCs and ovalbumin (OVA)-induced asthmatic rats were applied. Cell proliferation was detected by CCK-8 and EdU assays. Western blotting was used to detect extracellular signal-regulated kinase (ERK) 1/2, Drp1, autophagy-related markers and E-cadherin protein phosphorylation and expression. Inflammatory cytokines production, airway reactivity test, histological staining and immunohistochemical staining were conducted to evaluate the development of asthma. Transmission electron microscopy was used to observe the mitochondrial ultrastructure.

RESULTS

In primary cultured ASMCs, MIF increased the phosphorylation level of Drp1 at the Ser616 site through activation of the ERK1/2 signaling pathway, which further activated autophagy and reduced E-cadherin expression, ultimately leading to ASMCs proliferation. In OVA-induced asthmatic rats, MIF inhibitor 4-iodo-6-phenylpyrimidine (4-IPP) treatment, suppression of mitochondrial fission by Mdivi-1 or inhibiting autophagy with chloroquine phosphate (CQ) all attenuated the development of airway remodeling.

CONCLUSIONS

The present study provides novel insights that MIF promotes airway remodeling in asthma by activating autophagy and degradation of E-cadherin via ERK/Drp1 signaling pathway, suggesting that targeting MIF/ERK/Drp1 might have potential therapeutic value for the prevention and treatment of asthma.

Airway epithelial development and function: A key player in asthma pathogenesis?

Though asthma is a common and relatively easy to diagnose disease, attempts at primary or secondary prevention, and cure, have been disappointing. The widespread use of inhaled steroids has dramatically improved asthma control but has offered nothing in terms of altering long-term outcomes or reversing airway remodeling and impairment in lung function. The inability to cure asthma is unsurprising given our limited understanding of the factors that contribute to disease initiation and persistence. New data have focused on the airway epithelium as a potentially key factor orchestrating the different stages of asthma. In this review we summarize for the clinician the current evidence on the central role of the airway epithelium in asthma pathogenesis and the factors that may alter epithelial integrity and functionality.

Epithelial-Mesenchymal Transition Mechanisms in Chronic Airway Diseases: A Common Process to Target?

Epithelial-to-mesenchymal transition (EMT) is a reversible process, in which epithelial cells lose their epithelial traits and acquire a mesenchymal phenotype. This transformation has been described in different lung diseases, such as lung cancer, interstitial lung diseases, asthma, chronic obstructive pulmonary disease and other muco-obstructive lung diseases, such as cystic fibrosis and non-cystic fibrosis bronchiectasis. The exaggerated chronic inflammation typical of these pulmonary diseases can induce molecular reprogramming with subsequent self-sustaining aberrant and excessive profibrotic tissue repair. Over time this process leads to structural changes with progressive organ dysfunction and lung function impairment. Although having common signalling pathways, specific triggers and regulation mechanisms might be present in each disease. This review aims to describe the various mechanisms associated with fibrotic changes and airway remodelling involved in chronic airway diseases. Having better knowledge of the mechanisms underlying the EMT process may help us to identify specific targets and thus lead to the development of novel therapeutic strategies to prevent or limit the onset of irreversible structural changes.

ISL1 regulates lung branching morphogenesis via Shh signaling pathway

Lung branching morphogenesis relies on a complex coordination of multiple signaling pathways and transcription factors. Here, we found that ablation of the LIM homeodomain transcription factor Islet1 (Isl1) in lung epithelium resulted in defective branching morphogenesis and incomplete formation of five lobes. A reduction in mesenchymal cell proliferation was observed in Isl1ShhCre lungs. There was no difference in apoptosis between the wild-type (ShhCre) and Isl1ShhCre embryos. RNA-Seq and in situ hybridization analysis showed that Shh, Ptch1, Sox9, Irx1, Irx2, Tbx2, and Tbx3 were downregulated in the lungs of Isl1ShhCre embryos. ChIP assay implied the Shh gene served as a direct target of ISL1, since the transcription factor ISL1 could bind to the Shh epithelial enhancer sequence (MACS1). Also, activation of the Hedgehog pathway via ectopic gene expression rescued the defects caused by Isl1 ablation, confirming the genetic integration of Hedgehog signaling. In conclusion, our works suggest that epithelial Isl1 regulates lung branching morphogenesis through administrating the Shh signaling mediated epithelial-mesenchymal communications.

Engineering the Interactions of Classical Cadherin Cell-Cell Adhesion Proteins

Classical cadherins are calcium-dependent cell-cell adhesion proteins that play key roles in the formation and maintenance of tissues. Deficiencies in cadherin adhesion are hallmarks of numerous cancers. In this article, we review recent biophysical studies on the regulation of cadherin structure and adhesion. We begin by reviewing distinct cadherin binding conformations, their biophysical properties, and their response to mechanical stimuli. We then describe biophysical guidelines for engineering Abs that can regulate adhesion by either stabilizing or destabilizing cadherin interactions. Finally, we review molecular mechanisms by which cytoplasmic proteins regulate the conformation of cadherin extracellular regions from the inside out.

Spatially Resolved Proteomics Reveals Lens Suture-Related Cell-Cell Junctional Protein Distributions

Purpose

Lens transparency relies on the precise organization of lens fiber cells. The formation of the highly ordered lens architecture results from not only cell-cell adhesion along the lateral interfaces, but also from proper organization of fiber cells tips at lens sutures. Little is known about the cell adhesion between fiber tips at the sutures. The purpose of this study is to map suture-specific protein distributions.

Methods

Tissue sections were obtained from fresh frozen bovine lenses and washes were performed to remove soluble proteins and to retain membrane and membrane associated proteins. Imaging mass spectrometry (IMS) combined with on-tissue trypsin digestion was used to visualize protein spatial distributions. Sutures and adjacent regions were captured by laser capture microdissection and samples were digested by trypsin. Proteins were analyzed by liquid chromatography tandem MS and quantified by label-free quantification. Protein spatial distributions were confirmed by immunofluorescence.

Results

IMS results showed enrichment of adherens junction proteins cadherin-2 and armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF) in both anterior and posterior sutures of bovine lenses. Liquid chromatography tandem MS confirmed higher expression of cadherin-2 and ARVCF and other adherens junction proteins including catenin α2 (CTNNA2) and catenin β1 (CTNNB1) in sutures. In contrast, IMS indicated low expression of gap junction protein connexin 50 and connexin 46 in the suture regions. The localization of cadherin-2 and connexin 50 was confirmed by immunofluorescence.

Conclusions

The complementary expression of adherens junction proteins and gap junction proteins in lens suture regions implicates adherens junctions in fiber cell tip adhesion and in maintaining the integrity of the lens.

ADP Ribosylation Factor 6 Relieves Airway Inflammation and Remodeling by Inhibiting Ovalbumin Induced-Epithelial Mesenchymal Transition in Experimental Asthma, Possibly by Regulating of E2F Transcription Factor 8

BACKGROUND

Childhood asthma is a major global health concern. ADP-ribosylation factor 6 (ARF6) is a low-molecular-weight GTPase; however, its role in childhood asthma remains unclear.

METHODS

Ovalbumin (OVA)-challenged neonatal mice and transforming growth factor-β1 (TGF-β1)-induced BEAS-2B cells were used as in vivo and in vitro models of childhood asthma, respectively.

RESULTS

Upon OVA stimulation, ARF6 expression was upregulated in the lung tissue. Neonatal mice administered SehinH3 (an ARF6 inhibitor) exhibited improved pulmonary pathological injury, along with reduced inflammatory cell infiltration in the lungs and cytokine release in bronchial alveolar lavage fluid and serum (interleukin [IL]-3, IL-5, IL-13, IgE, and OVA-specific IgE). SehinH3 treatment restrained epithelial - mesenchymal transition (EMT) in the lungs of asthmatic mice, as evidenced by increased E-cadherin and decreased N-cadherin and α-smooth muscle actin expression. Different TGF-β1 exposures to BEAS-2B cells induced a time- and dose-dependent increase in ARF6 expression in vitro. Upon TGF-β1 stimulation, ARF6 knockdown repressed EMT and SehinH3 treatment caused similar results in BEAS-2B cells. The transcription factor E2F8 is involved in diverse biological functions and its increased expression was confirmed in vivo and in vitro. Dual-luciferase assays confirmed that E2F8 binds to the ARF6 promoter and promotes its transcriptional activity. In vitro results revealed that E2F8 silencing suppressed EMT, whereas rescue experiments showed that ARF6 overexpression partly reversed these phenomena.

CONCLUSION

Our study showed that ARF6 is associated with childhood asthma progression and may be positively regulated by E2F8. These results provide insight into the pathogenesis and treatment of childhood asthma.

Secreted S100A4 causes asthmatic airway epithelial barrier dysfunction induced by house dust mite extracts via activating VEGFA/VEGFR2 pathway

The airway epithelial barrier dysfunction plays a crucial role in pathogenesis of asthma and causes the amplification of downstream inflammatory signal pathway. S100 calcium binding protein A4 (S100A4), which promotes metastasis, have recently been discovered as an effective inflammatory factor and elevated in bronchoalveolar lavage fluid in asthmatic mice. Vascular endothelial growth factor-A (VEGFA), is considered as vital regulator in vascular physiological activities. Here, we explored the probably function of S100A4 and VEGFA in asthma model dealt with house dust mite (HDM) extracts. Our results showed that secreted S100A4 caused epithelial barrier dysfunction, airway inflammation and the release of T-helper 2 cytokines through the activation of VEGFA/VEGFR2 signaling pathway, which could be partial reversed by S100A4 polyclonal antibody, niclosamide and S100A4 knockdown, representing a potential therapeutic target for airway epithelial barrier dysfunction in asthma.

Fungal Aeroallergens-The Impact of Climate Change

The incidence of allergic diseases worldwide is rapidly increasing, making allergies a modern pandemic. This article intends to review published reports addressing the role of fungi as causative agents in the development of various overreactivity-related diseases, mainly affecting the respiratory tract. After presenting the basic information on the mechanisms of allergic reactions, we describe the impact of fungal allergens on the development of the allergic diseases. Human activity and climate change have an impact on the spread of fungi and their plant hosts. Particular attention should be paid to microfungi, i.e., plant parasites that may be an underestimated source of new allergens.

Comparative study of cigarette smoke, Klebsiella pneumoniae, and their combination on airway epithelial barrier function in mice

BACKGROUND

The airway epithelium acts as a physical barrier to protect pulmonary airways against pathogenic microorganisms and toxic substances, such as cigarette smoke (CS), bacteria, and viruses. The disruption of the structural integrity and dysfunction of the airway epithelium is related to the occurrence and progression of chronic obstructive pulmonary disease.

PURPOSE

The aim of this study is to compare the effects of CS, Klebsiella pneumoniae (KP), and their combination on airway epithelial barrier function.

METHODS

The mice were exposed to CS, KP, and their combination from 1 to 8 weeks. After the cessation of CS and KP at Week 8, we observed the recovery of epithelial barrier function in mice for an additional 16 weeks. To compare the epithelial barrier function among different groups over time, the mice were sacrificed at Weeks 4, 8, 16, and 24 and then the lungs were harvested to detect the pulmonary pathology, inflammatory cytokines, and tight junction proteins. To determine the underlying mechanisms, the BEAS-2B cells were treated with an epidermal growth factor receptor (EGFR) inhibitor (AG1478).

RESULTS

The results of this study suggested that the decreased lung function, increased bronchial wall thickness (BWT), elevated inflammatory factors, and reduced tight junction protein levels were observed at Week 8 in CS-induced mice and these changes persisted until Week 16. In the KP group, increased BWT and elevated inflammatory factors were observed only at Week 8, whereas in the CS + KP group, decreased lung function, lung tissue injury, inflammatory cell infiltration, and epithelial barrier impairment were observed at Week 4 and persisted until Week 24. To further determine the mechanisms of CS, bacteria, and their combination on epithelial barrier injury, we investigated the changes of EGFR and its downstream protein in the lung tissues of mice and BEAS-2B cells. Our research indicated that CS, KP, or their combination could activate EGFR, which can phosphorylate and activate ERK1/2, and this effect was more pronounced in the CS + KP group. Furthermore, the EGFR inhibitor AG1478 suppressed the phosphorylation of ERK1/2 and subsequently upregulated the expression of ZO-1 and occludin. In general, these results indicated that the combination of CS and KP caused more severe and enduring damage to epithelial barrier function than CS or KP alone, which might be associated with EGFR/ERK1/2 signaling.

CONCLUSION

Epithelial barrier injury occurred earlier, was more severe, and had a longer duration when induced by the combination of CS and KP compared with the exposure to CS or KP alone, which might be associated with EGFR/ERK signaling.

The HDM allergen orchestra and its cysteine protease maestro: Stimulators of kaleidoscopic innate immune responses

House dust mite (HDM) encloses an explosive cocktail of allergenic proteins sensitizing hundreds of millions of people worldwide. To date, the innate cellular and molecular mechanism(s) orchestrating the HDM-induced allergic inflammation remains partially deciphered. Understanding the kaleidoscope of HDM-induced innate immune responses is hampered by (1) the large complexity of the HDM allergome with very diverse functional bioreactivities, (2) the perpetual presence of microbial compounds (at least LPS, β-glucan, chitin) promoting as well pro-Th2 innate signaling pathways and (3) multiple cross-talks involving structural, neuronal and immune cells. The present review provides an update on the innate immune properties, identified so far, of multiple HDM allergen groups. Experimental evidence highlights the importance of HDM allergens displaying protease or lipid-binding activities on the initiation of the allergic responses. Specifically, group 1 HDM cysteine proteases are considered as the key initiators of the allergic response through their capacities to impair the epithelial barrier integrity, to stimulate the release of pro-Th2 danger-associated molecular patterns (DAMPs) in epithelial cells, to produce super-active forms of IL-33 alarmin and to mature thrombin leading to Toll-like receptor 4 (TLR4) activation. Remarkably, the recently evidenced primary sensing of cysteine protease allergens by nociceptive neurons confirms the critical role of this HDM allergen group in the early events leading to Th2 differentiation.

lncRNA CRNDE Affects Th17/IL-17A and Inhibits Epithelial-Mesenchymal Transition in Lung Epithelial Cells Reducing Asthma Signs

Background

Asthma treatment is difficult due to disease heterogeneity and comorbidities. In addition, the development of drugs targeting the underlying mechanisms of asthma remains slow. We planned to identify the most upregulated differentially expressed long noncoding RNA in asthma to explore its regulatory patterns and pathways in asthma.

Methods

We sensitized mice using a mixture of ovalbumin, house dust mites, and lipopolysaccharide to establish an asthma mouse model. We also sensitized asthma cells with TGF-β1 in an in vitro model. We performed a microarray analysis to identify the lncRNA with the differential expression level in model mice. We applied hematoxylin and eosin and Masson's trichrome stainings to mouse tissues to quantify the tissue damage extent. Next, we assess the levels of lncRNA CRNDE, miR-29a-3p, TGF-β1, MCL-1, E-cadherin, vimentin, and snail. We counted the percentages of Th17 cells using flow cytometry. Finally, we performed a dual-luciferase reporter assay to assess the association between lncRNA CRNDE and miR-29a-3p.

Results

We successfully established asthma mouse/cell models and selected the lncRNA CRNDE for our study. Transfection of si-CRNDE reduced the degree of injury and inflammation in the mouse model and reversed the TGF-β1-induced epithelial-mesenchymal transition (EMT) in the cell model. Moreover, the E-cadherin level was upregulated, and the levels of IL-17A, vimentin, snail, and α-SMA were downregulated. We also discovered that lncRNA CRNDE negatively regulated miR-29a-3p and that this one in turn inhibited MCL-1 in mice. After lncRNA CRNDE expression downregulation, the level of miR-29a-3p was increased, and we detected reduced levels of MCL-1 and EMTs.

Conclusions

lncRNA CRNDE expression downregulation led to reduced inflammation and reduced lung damage in mice with induced asthma, it inhibited the EMTs of lung epithelial cells via the miR-29a-3p/MCL-1 pathway, and it reduced the levels of Th17/IL-17A cells to reduce asthma signs.

Alpha-1 antitrypsin limits neutrophil extracellular trap disruption of airway epithelial barrier function

Neutrophil extracellular traps contribute to lung injury in cystic fibrosis and asthma, but the mechanisms are poorly understood. We sought to understand the impact of human NETs on barrier function in primary human bronchial epithelial and a human airway epithelial cell line. We demonstrate that NETs disrupt airway epithelial barrier function by decreasing transepithelial electrical resistance and increasing paracellular flux, partially by NET-induced airway cell apoptosis. NETs selectively impact the expression of tight junction genes claudins 4, 8 and 11. Bronchial epithelia exposed to NETs demonstrate visible gaps in E-cadherin staining, a decrease in full-length E-cadherin protein and the appearance of cleaved E-cadherin peptides. Pretreatment of NETs with alpha-1 antitrypsin (A1AT) inhibits NET serine protease activity, limits E-cadherin cleavage, decreases bronchial cell apoptosis and preserves epithelial integrity. In conclusion, NETs disrupt human airway epithelial barrier function through bronchial cell death and degradation of E-cadherin, which are limited by exogenous A1AT.

Tight Junctions, the Epithelial Barrier, and Toll-like Receptor-4 During Lung Injury

Lung epithelium is constantly exposed to the environment and is critically important for the orchestration of initial responses to infectious organisms, toxins, and allergic stimuli, and maintenance of normal gaseous exchange and pulmonary function. The integrity of lung epithelium, fluid balance, and transport of molecules is dictated by the tight junctions (TJs). The TJs are formed between adjacent cells. We have focused on the topic of the TJ structure and function in lung epithelial cells. This review includes a summary of the last twenty years of literature reports published on the disrupted TJs and epithelial barrier in various lung conditions and expression and regulation of specific TJ proteins against pathogenic stimuli. We discuss the molecular signaling and crosstalk among signaling pathways that control the TJ structure and function. The Toll-like receptor-4 (TLR4) recognizes the pathogen- and damage-associated molecular patterns released during lung injury and inflammation and coordinates cellular responses. The molecular aspects of TLR4 signaling in the context of TJs or the epithelial barrier are not fully known. We describe the current knowledge and possible networking of the TLR4-signaling with cellular and molecular mechanisms of TJs, lung epithelial barrier function, and resistance to treatment strategies.

Comprehensive analysis of prognostic significance of cadherin (CDH) gene family in breast cancer

Breast cancer is one of the leading deaths in all kinds of malignancies; therefore, it is important for early detection. At the primary tumor site, tumor cells could take on mesenchymal properties, termed the epithelial-to-mesenchymal transition (EMT). This process is partly regulated by members of the cadherin (CDH) family of genes, and it is an essential step in the formation of metastases. There has been a lot of study of the roles of some of the CDH family genes in cancer; however, a holistic approach examining the roles of distinct CDH family genes in the development of breast cancer remains largely unexplored. In the present study, we used a bioinformatics approach to examine expression profiles of CDH family genes using the Oncomine, Gene Expression Profiling Interactive Analysis 2 (GEPIA2), cBioPortal, MetaCore, and Tumor IMmune Estimation Resource (TIMER) platforms. We revealed that CDH1/2/4/11/12/13 messenger (m)RNA levels are overexpressed in breast cancer cells compared to normal cells and were correlated with poor prognoses in breast cancer patients’ distant metastasis-free survival. An enrichment analysis showed that high expressions of CDH1/2/4/11/12/13 were significantly correlated with cell adhesion, the extracellular matrix remodeling process, the EMT, WNT/beta-catenin, and interleukin-mediated immune responses. Collectively, CDH1/2/4/11/12/13 are thought to be potential biomarkers for breast cancer progression and metastasis.

HDAC6 inhibitor ACY-1083 shows lung epithelial protective features in COPD

Airway epithelial damage is a common feature in respiratory diseases such as COPD and has been suggested to drive inflammation and progression of disease. These features manifest as remodeling and destruction of lung epithelial characteristics including loss of small airways which contributes to chronic airway inflammation. Histone deacetylase 6 (HDAC6) has been shown to play a role in epithelial function and dysregulation, such as in cilia disassembly, epithelial to mesenchymal transition (EMT) and oxidative stress responses, and has been implicated in several diseases. We thus used ACY-1083, an inhibitor with high selectivity for HDAC6, and characterized its effects on epithelial function including epithelial disruption, cytokine production, remodeling, mucociliary clearance and cell characteristics. Primary lung epithelial air-liquid interface cultures from COPD patients were used and the impacts of TNF, TGF-β, cigarette smoke and bacterial challenges on epithelial function in the presence and absence of ACY-1083 were tested. Each challenge increased the permeability of the epithelial barrier whilst ACY-1083 blocked this effect and even decreased permeability in the absence of challenge. TNF was also shown to increase production of cytokines and mucins, with ACY-1083 reducing the effect. We observed that COPD-relevant stimulations created damage to the epithelium as seen on immunohistochemistry sections and that treatment with ACY-1083 maintained an intact cell layer and preserved mucociliary function. Interestingly, there was no direct effect on ciliary beat frequency or tight junction proteins indicating other mechanisms for the protected epithelium. In summary, ACY-1083 shows protection of the respiratory epithelium during COPD-relevant challenges which indicates a future potential to restore epithelial structure and function to halt disease progression in clinical practice.

Destiny of airway disease: interplay between epithelial barrier and the innate immune system

When the organism encounters a foreign substance, it responds with mutual and regular interactions at different stages of the immune system. In airway diseases, the first encounter is at the epithelial level, where innate immune cells and their responses form the first leg of the protective mechanism. The most important barrier for environmental damage is the epithelial barrier. However, the epithelial barrier is not just a mechanical barrier. The formation of the microbiome on the epithelium and the tolerance or intolerance to environmental factors are vital. This vital balance is maintained between the epithelial surface and the subepithelial innate immune system. This is achieved by the epithelial line, which is a mechanical and functional barrier between them. In this respect, epithelial barrier function preservation has an important role in the development and prognosis of airway disease.

Histological characteristics of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases-1 in asthmatic murine model during A(H1N1)pdm09 infection

Pandemic influenza virus A(H1N1)pdm09 infection occurred in healthy children and young adults, but asthmatic patients presented more rapid progression of respiratory distress and plastic bronchitis. To investigate the pathogenesis of worsening respiratory symptoms after A(H1N1)pdm09 infection, we focused on matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1). MMP-9 and TIMP-1 levels in bronchoalveolar lavage fluid and serum from mice with and without asthma were evaluated after A(H1N1)pdm09 or seasonal A(H1N1) infection. MMP-9 levels were more elevated in Asthma/A(H1N1)pdm09-infected mice than in non-Asthma/A(H1N1)pdm09-infected mice on both 3 and 7 days post-infection. Immunohistochemical findings in this pneumonia model showed that MMP-9 and TIMP-1 positive cells were observed in blood vessels and bronchus of lung tissue in severe pathological findings of pneumonia with asthma. Microscopically, shedding cells and secretions were conspicuous in the trachea on days 3 and 7 post-infection, in the A(H1N1)pdm09-infected mice with asthma. Our results suggest that MMP-9 and TIMP-1 expressions are related to severe pneumonia in the A(H1N1)pdm09 infection with asthma, leading to cause epithelial cell shedding.

Hypoxia pretreatment enhances the therapeutic potential of mesenchymal stem cells (BMSCs) on ozone-induced lung injury in rats

Ozone (O₃) gas is a double-sided weapon. It provides a shield that protects life on earth from the harmful ultraviolet (UV) rays, but ground-level O₃ is considered an urban air pollutant. So, a rat model of chronic O₃ inhalation was established to assess the biochemical and morphological alterations in the lung tissue and to investigate the ameliorative effects of bone marrow-derived mesenchymal stem cells (BMSCs) with or without hypoxia pre-treatment. Forty-two adult male albino rats were divided into four groups: control, ozone-exposed, normoxic BMSC-treated, and hypoxic BMSC-treated groups. Lung tissue sections were processed for light and electron microscope examination, immunohistochemical staining for caspase 3, and iNOS. Quantitative real-time PCR for IL-1α, IL-17, TNF-α, and Nrf2 mRNA gene expression were also performed. Chronic O₃ exposure caused elevated inflammatory cytokines and decreased antioxidant Nrf2 mRNA expression. Marked morphological alterations with increased collagen deposition and elevated apoptotic markers and iNOS were evident. BMSC treatment showed immunomodulatory (decreased inflammatory cytokine gene expression), antioxidant (increased Nrf2 expression and decreased iNOS), and anti-apoptotic (decreased caspase3 expression) effects. Consequently, ameliorated lung morphology with diminished collagen deposition was observed. Hypoxia pretreatment enhanced BMSC survival by MTT assay. It also augmented the previously mentioned effects of BMSCs on the lung tissue as proved by statistical analysis. Lung morphology was similar to that of control group. In conclusion, hypoxia pretreatment represents a valuable intervention to enhance the effects of MSCs on chronic lung injury.

The relation between age and airway epithelial barrier function

Background

The prevalence of age-associated diseases, such as chronic obstructive pulmonary disease (COPD), is increasing as the average life expectancy increases around the world. We previously identified a gene signature for ageing in the human lung which included genes involved in apical and tight junction assembly, suggesting a role for airway epithelial barrier dysfunction with ageing.

Aim

To investigate the association between genes involved in epithelial barrier function and age both in silico and in vitro in the airway epithelium.

Methods

We curated a gene signature of 274 genes for epithelial barrier function and tested the association with age in two independent cohorts of bronchial brushings from healthy individuals with no respiratory disease, using linear regression analysis (FDR < 0.05). Protein–protein interactions were identified using STRING©. The barrier function of primary bronchial epithelial cells at air–liquid interface and CRISPR–Cas9-induced knock-down of target genes in human bronchial 16HBE14o-cells was assessed using Trans epithelial resistance (TER) measurement and Electric cell-surface impedance sensing (ECIS) respectively.

Results

In bronchial brushings, we found 55 genes involved in barrier function to be significantly associated with age (FDR < 0.05). EPCAM was most significantly associated with increasing age and TRPV4 with decreasing age. Protein interaction analysis identified CDH1, that was negatively associated with higher age, as potential key regulator of age-related epithelial barrier function changes. In vitro, barrier function was lower in bronchial epithelial cells from subjects > 45 years of age and significantly reduced in CDH1-deficient 16HBE14o-cells.

Conclusion

The significant association between genes involved in epithelial barrier function and age, supported by functional studies in vitro, suggest a role for epithelial barrier dysfunction in age-related airway disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01961-7.

Promotor Hypomethylation Mediated Upregulation of miR-23b-3p Targets PTEN to Promote Bronchial Epithelial-Mesenchymal Transition in Chronic Asthma

Chronic asthma is characterized by airway inflammation and irreversible airway remodeling. Epithelial-mesenchymal transition (EMT) is a typical pathological change of airway remodeling. Our previous research demonstrated miR-23b inhibited airway smooth muscle proliferation while the function of miR-23b-3p has not been reported yet. Besides, miRNA is regulated by many factors, including DNA methylation. The function of miR-23b-3p and whether it is regulated by DNA methylation are worth exploring. Balb/c mice were given OVA sensitization to develop the asthmatic model. Expression of miR-23b-3p and EMT markers were measured by RT-qPCR, WB and immunohistochemistry (IHC). DNA methylation was detected by methylation-specific PCR (MSP) and the MassARRAY System. Asthmatic mice and TGF-β1-stimulated bronchial epithelial cells (BEAS-2B) showed EMT with increased miR-23b-3p. Overexpression of miR-23b-3p promoted EMT and migration, while inhibition of miR-23b-3p reversed these transitions. DNA methyltransferases were decreased in asthmatic mice. MSP and MassARRAY System detected the promotor of miR-23b showed DNA hypomethylation. DNA methyltransferase inhibitor 5’-AZA-CdZ increased the expression of miR-23b-3p. Meanwhile, PTEN was identified as a target gene of miR-23b-3p. Our results indicated that promotor hypomethylation mediated upregulation of miR-23b-3p targets PTEN to promote EMT in chronic asthma. miR-23b-3p and DNA methylation might be potential therapeutic targets for irreversible airway remodeling.

Cell monolayer deformation microscopy reveals mechanical fragility of cell monolayers following EMT

Tissue and cell mechanics are crucial factors in maintaining homeostasis and in development, with aberrant mechanics contributing to many diseases. During the epithelial-to-mesenchymal transition (EMT), a highly conserved cellular program in organismal development and cancer metastasis, cells gain the ability to detach from their original location and autonomously migrate. While a great deal of biochemical and biophysical changes at the single-cell level have been revealed, how the physical properties of multicellular assemblies change during EMT, and how this may affect disease progression, is unknown. Here we introduce cell monolayer deformation microscopy (CMDM), a new methodology to measure the planar mechanical properties of cell monolayers by locally applying strain and measuring their resistance to deformation. We employ this new method to characterize epithelial multicellular mechanics at early and late stages of EMT, finding the epithelial monolayers to be relatively compliant, ductile, and mechanically homogeneous. By comparison, the transformed mesenchymal monolayers, while much stiffer, were also more brittle, mechanically heterogeneous, displayed more viscoelastic creep, and showed sharp yield points at significantly lower strains. Here, CMDM measurements identify specific biophysical functional states of EMT and offer insight into how cell aggregates fragment under mechanical stress. This mechanical fingerprinting of multicellular assemblies using new quantitative metrics may also offer new diagnostic applications in healthcare to characterize multicellular mechanical changes in disease.

Identification of Core Genes and Pathways in Melanoma Metastasis via Bioinformatics Analysis

Metastasis is the leading cause of melanoma-related mortality. Current therapies are rarely curative for metastatic melanoma, revealing the urgent need to identify more effective preventive and therapeutic targets. This study aimed to screen the core genes and molecular mechanisms related to melanoma metastasis. A gene expression profile, GSE8401, including 31 primary melanoma and 52 metastatic melanoma clinical samples, was downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) between melanoma metastases and primary melanoma were screened using GEO2R tool. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) analyses of DEGs were performed using the Database for Annotation Visualization and Integrated Discovery (DAVID). The Search Tool for the Retrieval of Interacting Genes (STRING) and Cytoscape with Molecular Complex Detection (MCODE) plug-in tools were utilized to detect the protein–protein interaction (PPI) network among DEGs. The top 10 genes with the highest degrees of the PPI network were defined as hub genes. In the results, 425 DEGs, including 60 upregulated genes and 365 downregulated genes, were identified. The upregulated genes were enriched in ECM–receptor interactions and the regulation of actin cytoskeleton, while 365 downregulated genes were enriched in amoebiasis, melanogenesis, and ECM–receptor interactions. The defined hub genes included CDK1, COL17A1, EGFR, DSG1, KRT14, FLG, CDH1, DSP, IVL, and KRT5. In addition, the mRNA and protein levels of the hub genes during melanoma metastasis were verified in the TCGA database and paired post- and premetastatic melanoma cells, respectively. Finally, KRT5-specific siRNAs were utilized to reduce the KRT5 expression in melanoma A375 cells. An MTT assay and a colony formation assay showed that KRT5 knockdown significantly promoted the proliferation of A375 cells. A Transwell assay further suggested that KRT5 knockdown significantly increased the cell migration and cell invasion of A375 cells. This bioinformatics study provided a deeper understanding of the molecular mechanisms of melanoma metastasis. The in vitro experiments showed that KRT5 played the inhibitory effects on melanoma metastasis. Therefore, KRT5 may serve important roles in melanoma metastasis.

Endocannabinoid Anandamide Attenuates Acute Respiratory Distress Syndrome through Modulation of Microbiome in the Gut-Lung Axis

Acute respiratory distress syndrome (ARDS) is a serious lung condition characterized by severe hypoxemia leading to limitations of oxygen needed for lung function. In this study, we investigated the effect of anandamide (AEA), an endogenous cannabinoid, on Staphylococcal enterotoxin B (SEB)-mediated ARDS in female mice. Single-cell RNA sequencing data showed that the lung epithelial cells from AEA-treated mice showed increased levels of antimicrobial peptides (AMPs) and tight junction proteins. MiSeq sequencing data on 16S RNA and LEfSe analysis demonstrated that SEB caused significant alterations in the microbiota, with increases in pathogenic bacteria in both the lungs and the gut, while treatment with AEA reversed this effect and induced beneficial bacteria. AEA treatment suppressed inflammation both in the lungs as well as gut-associated mesenteric lymph nodes (MLNs). AEA triggered several bacterial species that produced increased levels of short-chain fatty acids (SCFAs), including butyrate. Furthermore, administration of butyrate alone could attenuate SEB-mediated ARDS. Taken together, our data indicate that AEA treatment attenuates SEB-mediated ARDS by suppressing inflammation and preventing dysbiosis, both in the lungs and the gut, through the induction of AMPs, tight junction proteins, and SCFAs that stabilize the gut-lung microbial axis driving immune homeostasis.

Fundamentals of vaping-associated pulmonary injury leading to severe respiratory distress

Vaping of flavored liquids has been touted as safe alternative to traditional cigarette smoking with decreased health risks. The popularity of vaping has dramatically increased over the last decade, particularly among teenagers who incorporate vaping into their daily life as a social activity. Despite widespread and increasing adoption of vaping among young adults, there is little information on long-term consequences of vaping and potential health risks. This study demonstrates vaping-induced pulmonary injury using commercial JUUL pens with flavored vape juice using an inhalation exposure murine model. Profound pathological changes to upper airway, lung tissue architecture, and cellular structure are evident within 9 wk of exposure. Marked histologic changes include increased parenchyma tissue density, cellular infiltrates proximal to airway passages, alveolar rarefaction, increased collagen deposition, and bronchial thickening with elastin fiber disruption. Transcriptional reprogramming includes significant changes to gene families coding for xenobiotic response, glycerolipid metabolic processes, and oxidative stress. Cardiac systemic output is moderately but significantly impaired with pulmonary side ventricular chamber enlargement. This vaping-induced pulmonary injury model demonstrates mechanistic underpinnings of vaping-related pathologic injury.

PM2.5 Aggravated OVA-Induced Epithelial Tight Junction Disruption Through Fas Associated via Death Domain-Dependent Apoptosis in Asthmatic Mice

BACKGROUND

Exposure to air pollutants cause exacerbation of asthma, but the experimental evidence and the mechanisms still need to be collected and addressed.

METHODS

Asthma model was constructed by ovalbumin (OVA) combined with or without airborne fine particulate matter 2.5 (PM2.5) exposure. Lung sections were stained by hematoxylin-eosin staining (H&E) and Masson's trichrome. RNA-seq and gene set enrichment analysis (GSEA) was performed to identify the key pathway. TdT mediated dUTP Nick End Labeling (TUNEL) assay, real-time qPCR, Western blot, immunofluorescence and lentivirus transfection were applied for mechanism discovery.

RESULTS

In this study, we found PM2.5 aggravated airway inflammation in OVA-induced asthmatic mice. RNA-seq analysis also showed that epithelial mesenchymal transition (EMT) was enhanced in OVA-induced mice exposed to PM2.5 compared with that in OVA-induced mice. In the meantime, we observed that apoptosis was significantly increased in asthmatic mice exposed to PM2.5 by using GSEA analysis, which was validated by TUNEL assay. By using bioinformatic analysis, Fas associated via death domain (FADD), a new actor in innate immunity and inflammation, was identified to be related to apoptosis, EMT and tight junction. Furthermore, we found that the transcript and protein levels of tight junction markers, E-cadherin, zonula occludens (ZO)-1 and Occludin, were decreased after PM2.5 exposure in vivo and in vitro by using RT-qPCR and immunofluorescence, with the increased expression of FADD. Moreover, down-regulation of FADD attenuated PM2.5-induced apoptosis and tight junction disruption in human airway epithelial cells.

CONCLUSION

Taken together, we demonstrated that PM2.5 aggravated epithelial tight junction disruption through apoptosis mediated by up-regulation of FADD in OVA-induced model.

Short-Term Preclinical Application of Functional Human Induced Pluripotent Stem Cell-Derived Airway Epithelial Patches

Airway pathologies including cancer, trauma, and stenosis lack effective treatments, meanwhile airway transplantation and available tissue engineering approaches fail due to epithelial dysfunction. Autologous progenitors do not meet the clinical need for regeneration due to their insufficient expansion and differentiation, for which human induced pluripotent stem cells (hiPSCs) are promising alternatives. Airway epithelial patches are engineered by differentiating hiPSC-derived airway progenitors into physiological proportions of ciliated (73.9 ± 5.5%) and goblet (2.1 ± 1.4%) cells on a silk fibroin-collagen vitrigel membrane (SF-CVM) composite biomaterial for transplantation in porcine tracheal defects ex vivo and in vivo. Evaluation of ex vivo tracheal repair using hiPSC-derived SF-CVM patches demonstrate native-like tracheal epithelial metabolism and maintenance of mucociliary epithelium to day 3. In vivo studies demonstrate SF-CVM integration and maintenance of airway patency, showing 80.8 ± 3.6% graft coverage with an hiPSC-derived pseudostratified epithelium and 70.7 ± 2.3% coverage with viable cells, 3 days postoperatively. The utility of bioengineered, hiPSC-derived epithelial patches for airway repair is demonstrated in a short-term preclinical survival model, providing a significant leap for airway reconstruction approaches.

The Emerging Roles of Tripartite Motif Proteins (TRIMs) in Acute Lung Injury

Acute lung injury (ALI) is an inflammatory disorder of the lung that causes high mortality and lacks any pharmacological intervention. Ubiquitination plays a critical role in the pathogenesis of ALI as it regulates the alveolocapillary barrier and the inflammatory response. Tripartite motif (TRIM) proteins are one of the subfamilies of the RING-type E3 ubiquitin ligases, which contains more than 80 distinct members in humans involved in a broad range of biological processes including antivirus innate immunity, development, and tumorigenesis. Recently, some studies have shown that several members of TRIM family proteins play important regulatory roles in inflammation and ALI. Herein, we integrate emerging evidence regarding the roles of TRIMs in ALI. Articles were selected from the searches of PubMed database that had the terms "acute lung injury," "ubiquitin ligases," "tripartite motif protein," "inflammation," and "ubiquitination" using both MeSH terms and keywords. Better understanding of these mechanisms may ultimately lead to novel therapeutic approaches by targeting TRIMs for ALI treatment.

E-Cadherin: An Important Functional Molecule at Respiratory Barrier Between Defence and Dysfunction

While breathing, many microorganisms, harmful environmental particles, allergens, and environmental pollutants enter the human airways. The human respiratory tract is lined with epithelial cells that act as a functional barrier to these harmful factors and provide homeostasis between external and internal environment. Intercellular epithelial junctional proteins play a role in the formation of the barrier. E-cadherin is a calcium-dependent adhesion molecule and one of the most important molecules involved in intercellular epithelial barier formation. E-cadherin is not only physical barrier element but also regulates cell proliferation, differentiation and the immune response to environmental noxious agents through various transcription factors. In this study, we aimed to review the role of E-cadherin in the formation of airway epithelial barier, its status as a result of exposure to various environmental triggers, and respiratory diseases associated with its dysfunction. Moreover, the situations in which its abnormal activation can be noxious would be discussed.

E-Cadherin Expression and Blunted Interferon Response in Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive neoplasm derived from plasmacytoid dendritic cells (pDCs). In this study, we investigated by immunohistochemical analysis the expression of E-cadherin (EC) on pDCs in reactive lymph nodes and tonsils, bone marrow, and in BPDCN. We compared the expression of EC in BPDCN to that in leukemia cutis (LC) and cutaneous lupus erythematosus (CLE), the latter typically featuring pDC activation. In BPDCN, we also assessed the immunomodulatory activity of malignant pDCs through the expression of several type I interferon (IFN-I) signaling effectors and downstream targets, PD-L1/CD274, and determined the extent of tumor infiltration by CD8-expressing T cells. In reactive lymph nodes and tonsils, pDCs expressed EC, whereas no reactivity was observed in bone marrow pDCs. BPDCN showed EC expression in the malignant pDCs in the vast majority of cutaneous (31/33 cases, 94%), nodal, and spleen localizations (3/3 cases, 100%), whereas it was more variable in the bone marrow (5/13, 38,5%), where tumor cells expressed EC similarly to the skin counterpart in 4 cases and differently in other 4. Notably, EC was undetectable in LC (n=30) and in juxta-epidermal pDCs in CLE (n=31). Contrary to CLE showing robust expression of IFN-I-induced proteins MX1 and ISG5 in 20/23 cases (87%), and STAT1 phosphorylation, BPDCN biopsies showed inconsistent levels of these proteins in most cases (85%). Expression of IFN-I-induced genes, IFI27, IFIT1, ISG15, RSAD2, and SIGLEC1, was also significantly (P<0.05) lower in BPDCN as compared with CLE. In BPDCN, a significantly blunted IFN-I response correlated with a poor CD8+T-cell infiltration and the lack of PD-L1/CD274 expression by the tumor cells. This study identifies EC as a novel pDC marker of diagnostic relevance in BPDCN. The results propose a scenario whereby malignant pDCs through EC-driven signaling promote the blunting of IFN-I signaling and, thereby, the establishment of a poorly immunogenic tumor microenvironment.

Inflammation in Asthma Pathogenesis: Role of T cells, Macrophages, Epithelial Cells and Type 2 Inflammation

Asthma is a chronic disease with abnormal inflammatory and immunological responses. The disease initiated by antigens in subjects with genetic susceptibility. However, environmental factors play a role in the initiation and exacerbation of asthma attack. Asthma is T helper 2 (Th2)-cell-mediated disease. Recent studies indicated that asthma is not a single disease entity, but it is with multiple phenotypes and endotypes. The pathophysiological changes in asthma included a series of subsequent continuous vicious circle of cellular activation contributed to induction of chemokines and cytokines that potentiate inflammation. The heterogeneity of asthma influenced the treatment response. The asthma pathogenesis driven by varied set of cells such as eosinophils, basophils, neutrophils, mast cells, macrophages, epithelial cells and T cells. In this review the role of T cells, macrophage, and epithelial cells are discussed.

Recent advances in human respiratory epithelium models for drug discovery

The respiratory epithelium is intimately associated with the pathophysiologies of highly infectious viral contagions and chronic illnesses such as chronic obstructive pulmonary disorder, presently the third leading cause of death worldwide with a projected economic burden of £1.7 trillion by 2030. Preclinical studies of respiratory physiology have almost exclusively utilised non-humanised animal models, alongside reductionistic cell line-based models, and primary epithelial cell models cultured at an air-liquid interface (ALI). Despite their utility, these model systems have been limited by their poor correlation to the human condition. This has undermined the ability to identify novel therapeutics, evidenced by a 15% chance of success for medicinal respiratory compounds entering clinical trials in 2018. Consequently, preclinical studies require new translational efficacy models to address the problem of respiratory drug attrition. This review describes the utility of the current in vivo (rodent), ex vivo (isolated perfused lungs and precision cut lung slices), two-dimensional in vitro cell-line (A549, BEAS-2B, Calu-3) and three-dimensional in vitro ALI (gold-standard and co-culture) and organoid respiratory epithelium models. The limitations to the application of these model systems in drug discovery research are discussed, in addition to perspectives of the future innovations required to facilitate the next generation of human-relevant respiratory models.

Transcriptome-wide profiling discover: PM2.5 aggravates airway dysfunction through epithelial barrier damage regulated by Stanniocalcin 2 in an OVA-induced model

BACKGROUND

Epidemiologic evidence suggests that PM2.5 exposure aggravates asthma, but the molecular mechanisms are not fully discovered.

METHODS

Ovalbumin (OVA)-induced mice exposed to PM2.5 were constructed. Pathological staining and immunofluorescence were performed in in vivo study. Gene set enrichment analysis (GSEA) was performed to identify the pathway involved in asthma severity by using U-BIOPRED data (human bronchial biopsies) and RNA-seq data (Beas-2B cells treated with PM2.5). Lentiviruses transfection, Real-time qPCR, immunofluorescence staining and trans-epithelial electrical resistance (TEER) measurement were performed for mechanism exploration in vitro.

RESULTS

PM2.5 exposure aggravated airway inflammation and mucus secretion in OVA-induced mice. Based on transcriptome analysis of mild-to-severe asthma from human bronchial biopsies, gene set enrichment analysis (GSEA) showed that up-regulated reactive oxygen species (ROS) pathway gene set and down-regulated apical junction gene set correlated with asthma severity. Consistent with the analysis of mild-to-severe asthma, after PM2.5 exposure, the ROS pathway in Beas-2B cells was up-regulated with the down-regulation of apical junction. The expression levels of genes involved in the specific gene sets were validated by using qPCR. The mRNA levels of junction genes, ZO-1, E-cadherin and Occludin, were significantly decreased in cells exposed to PM2.5. Moreover, it confirmed that inhibition of ROS recovered the expression levels of E-cadherin, Occludin and ZO-1, and ameliorated inflammation and mucus secretion in airway in OVA-induced mice exposed to PM2.5. Meanwhile, ROS level was elevated by PM2.5. By checking trans-epithelial electrical resistance (TEER) value, we also found that epithelial barrier was damaged after PM2.5 exposure. Importantly, Stanniocalcin 2 (STC2) was identified as a key gene in regulation of epithelial barrier. It showed that STC2 expression was up-regulated by PM2.5, which was recovered by NAC as well. Over-expression of STC2 could decrease the expression levels of ZO-1, Occludin and E-cadherin. Contrarily, suppression of STC2 could increase the expression levels of ZO-1, Occludin and E-cadherin reduced by PM2.5.

CONCLUSIONS

By using transcriptome analysis, we revealed that STC2 played a key role in PM2.5 aggravated airway dysfunction through regulation of epithelial barrier in OVA-induced mice.

Inhibition of β-Catenin/CREB Binding Protein Signaling Attenuates House Dust Mite-Induced Goblet Cell Metaplasia in Mice

Excessive mucus production is a major feature of allergic asthma. Disruption of epithelial junctions by allergens such as house dust mite (HDM) results in the activation of β-catenin signaling, which has been reported to stimulate goblet cell differentiation. β-catenin interacts with various co-activators including CREB binding protein (CBP) and p300, thereby regulating the expression of genes involved in cell proliferation and differentiation, respectively. We specifically investigated the role of the β-catenin/CBP signaling pathway in goblet cell metaplasia in a HDM-induced allergic airway disease model in mice using ICG-001, a small molecule inhibitor that blocks the binding of CBP to β-catenin. Female 6- 8-week-old BALB/c mice were sensitized to HDM/saline on days 0, 1, and 2, followed by intranasal challenge with HDM/saline with or without subcutaneous ICG-001/vehicle treatment from days 14 to 17, and samples harvested 24 h after the last challenge/treatment. Differential inflammatory cells in bronchoalveolar lavage (BAL) fluid were enumerated. Alcian blue (AB)/Periodic acid–Schiff (PAS) staining was used to identify goblet cells/mucus production, and airway hyperresponsiveness (AHR) was assessed using invasive plethysmography. Exposure to HDM induced airway inflammation, goblet cell metaplasia and increased AHR, with increased airway resistance in response to the non-specific spasmogen methacholine. Inhibition of the β-catenin/CBP pathway using treatment with ICG-001 significantly attenuated the HDM-induced goblet cell metaplasia and infiltration of macrophages, but had no effect on eosinophils, neutrophils, lymphocytes or AHR. Increased β-catenin/CBP signaling may promote HDM-induced goblet cell metaplasia in mice.

Eosinophils Correlate with Epithelial-Mesenchymal Transition in Chronic Rhinosinusitis with Nasal Polyps

INTRODUCTION

Chronic inflammation and tissue remodeling always occur together in chronic rhinosinusitis (CRS). Epithelial-mesenchymal transition (EMT) plays a critical role in airway remodeling.

OBJECTIVE

Changes of epithelial cells in sinus mucosa in different subtypes of CRS, especially in eosinophilic chronic rhinosinusitis with nasal polyps, and the role of EMT and eosinophils (EOS) in airway remodeling are still unknown.

METHODS

We included 85 patients in this study. They were divided into 4 groups: a normal control (NC) group, a chronic rhinosinusitis without nasal polyps (CRSsNP) group, an eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) group, and a noneosinophilic chronic rhinosinusitis with nasal polyps (non-ECRSwNP) group. Clinical data were all collected and analyzed. Standard hematoxylin and eosin staining, immunohistochemical staining, and 2-color immunofluorescence staining were performed. Biomarkers of EMT, epithelial cadherin, and vimentin were labeled. The immunohistochemistry results of each group were counted and statistically analyzed.

RESULTS AND CONCLUSION

E-cadherin was downregulated, and vimentin was upregulated in epithelial tissue from the ECRSwNP group, compared with that from the control group and the other groups. The number of vimentin-expressing epithelial cells correlated with sinus CT imaging Lund-Mackay scores (r = 0.560, p < 0.001). Moreover, expression levels of vimentin in the epithelium were associated with numbers of infiltrating EOS in tissues (r = 0.710, p < 0.001) and the peripheral blood EOS ratio (r = 0.594, p < 0.001). EMT occurred in patients with CRSwNP, especially in those with ECRSwNP. Epithelial reprogramming correlates with eosinophil infiltration and disease severity. Eosinophils contributed to impairment of epithelial function and promoted EMT in CRSwNP.

AGR3 Regulates Airway Epithelial Junctions in Patients with Frequent Exacerbations of COPD

Background: The mechanisms underlying differences in the susceptibility to chronic obstructive pulmonary disease (COPD) exacerbations between patients are not well understood. Recent studies have shown that the patients with frequent COPD exacerbations is related to specific protein expression in lung tissue. Anterior gradient 3 (AGR3) is expressed in airway epithelial cells in the lung and proteomic analysis revealed that its expression is decreased in patients with frequent COPD exacerbations. Moreover, the loss of epithelial integrity might facilitate trans-epithelial permeability of pathogens in such patients. This study was performed to determine that AGR3 protein play a role in COPD frequency exacerbators. Methods: Human lung tissues were collected from current-smoking patients (Control; n = 15) as well as patients with infrequent COPD exacerbations (IFCOPD; n = 18) and frequent COPD exacerbations (FCOPD; n = 8). While AGR3 protein expression was measured by immunohistochemistry and western blotting, AGR mRNA expression was determined by real time quantitative polymerase chain reaction (RT-qPCR). Furthermore, adherent junctions (AJs) and tight junctions (TJs) protein expression in human lung tissues were measured by immunohistochemistry. The effects of cigarette smoke extract (CSE) on AJ and TJ protein and mRNA expression in BEAS-2B cells were assessed by western blotting and RT-qPCR. In addition, the effect of AGR3 overexpression and knockdown on AJ and TJ protein expression was determined. Results: AGR3 was mainly expressed in the airway epithelium and AGR3-positive products were localized in the cytoplasm. Western blotting and RT-qPCR results showed that AGR3 protein (p = 0.009) and mRNA (p = 0.04) expression in the FCOPD group was significantly lower than that in the IFCOPD group. Moreover, E-cadherin, occludin, and zonula occludens-1 (ZO-1) expression was lower in the FCOPD group than in the IFCOPD group. The protein and mRNA expression of E-cadherin, occludin, and ZO-1 was decreased within 24 h post-CSE exposure. AGR3 overexpression rescued CSE-induced downregulation of E-cadherin, occludin, and ZO-1. Conclusion: Difference in AGR3 expression in the lung tissue might be correlated with increased susceptibility to COPD exacerbation. AGR3 can prevent CSE-induced downregulation of E-cadherin, occludin, and ZO-1 in airway epithelial cells. Loss of AGR3 might promote viral and bacterial infection and induce immune inflammation to increase COPD exacerbation.

A Protective Role of FAM13A in Human Airway Epithelial Cells Upon Exposure to Cigarette Smoke Extract

Background

Chronic Obstructive Pulmonary Disease (COPD) is a progressive lung disease characterized by chronic inflammation upon inhalation of noxious particles, e.g., cigarette smoke. FAM13A is one of the genes often found to be associated with COPD, however its function in the pathophysiology of COPD is incompletely understood. We studied its role in airway epithelial barrier integrity and cigarette smoke-induced epithelial responses.

Materials and Methods

Protein level and localization of FAM13A was assessed with immunohistochemistry in lung tissue from COPD patients and non-COPD controls. In vitro, FAM13A expression was determined in the absence or presence of cigarette smoke extract (CSE) in primary airway epithelial cells (AECs) from COPD patients and controls by western blotting. FAM13A was overexpressed in cell line 16HBE14o- and its effect on barrier function was monitored real-time by electrical resistance. Expression of junctional protein E-cadherin and β-catenin was assessed by western blotting. The secretion of neutrophil attractant CXCL8 upon CSE exposure was measured by ELISA.

Results

FAM13A was strongly expressed in airway epithelium, but significantly weaker in airways of COPD patients compared to non-COPD controls. In COPD-derived AECs, but not those of controls, FAM13A was significantly downregulated by CSE. 16HBE14o- cells overexpressing FAM13A built up epithelial resistance significantly more rapidly, which was accompanied by higher E-cadherin expression and reduced CSE-induced CXCL8 levels.

Conclusion

Our data indicate that the expression of FAM13A is lower in airway epithelium of COPD patients compared to non-COPD controls. In addition, cigarette smoking selectively downregulates airway epithelial expression of FAM13A in COPD patients. This may have important consequences for the pathophysiology of COPD, as the more rapid build-up of epithelial resistance upon FAM13A overexpression suggests improved (re)constitution of barrier function. The reduced epithelial secretion of CXCL8 upon CSE-induced damage suggests that lower FAM13A expression upon cigarette smoking may facilitate epithelial-driven neutrophilia.

Epithelial Barrier Integrity Profiling: Combined Approach Using Cellular Junctional Complex Imaging and Transepithelial Electrical Resistance

A core aspect of epithelial cell function is barrier integrity. A loss of barrier integrity is a feature of a number of respiratory diseases, including asthma, allergic rhinitis, and chronic obstructive pulmonary disease. Restoration of barrier integrity is a target for respiratory disease drug discovery. Traditional methods for assessing barrier integrity have their limitations. Transepithelial electrical resistance (TEER) and dextran permeability methods can give poor in vitro assay robustness. Traditional junctional complex imaging approaches are labor-intensive and tend to be qualitative but not quantitative. To provide a robust and quantitative assessment of barrier integrity, high-content imaging of junctional complexes was combined with TEER. A scalable immunofluorescent high-content imaging technique, with automated quantification of junctional complex proteins zonula occludens-1 and occludin, was established in 3D pseudostratified primary human bronchial epithelial cells cultured at an air-liquid interface. Ionic permeability was measured using TEER on the same culture wells.The improvements to current technologies include the design of a novel 24-well holder to enable scalable in situ confocal cell imaging without Transwell membrane excision, the development of image analysis pipelines to quantify in-focus junctional complex structures in each plane of a Z stack, and the enhancement of the TEER data analysis process to enable statistical evaluation of treatment effects on barrier integrity. This novel approach was validated by demonstrating measurable changes in barrier integrity in cells grown under conditions known to perturb epithelial cell function.

Galectin-7 overexpression destroys airway epithelial barrier in transgenic mice

When the integrity of airway epithelium is destroyed, the ordered airway barrier no longer exists and increases sensitivity to viral infections and allergens, leading to the occurrence of airway inflammation such as asthma. Here, we found that galectin-7 transgenic(+) mice exhibited abnormal airway structures as embryos and after birth. These abnormalities included absent or substantially reduced pseudostratified columnar ciliated epithelium and increased monolayer cells with irregular arrangement and widening of intercellular spaces. Moreover, airway tissue from galectin-7 transgenic(+) mice showed evidence of impaired cell-cell junctions and decreased expression of zonula occludens-1(ZO-1) and E-cadherin. When treated with respiratory syncytial virus (RSV) or ovalbumin (OVA), galectin-7 transgenic(+) mice developed substantially increased bronchial epithelial detachment and apoptosis, airway smooth muscle and basement membrane thickening, and enhanced airway responsiveness. We found that Galectin-7 localized in the cytoplasm and nucleus of bronchial epithelial cells, and that increased apoptosis was mediated through mitochondrial release of cytochrome c and upregulated JNK1 activation and expression of caspase-3 in galectin-7 Tg(+) mice. These findings suggested that Galectin-7 causes airway structural defects and destroys airway epithelium barrier, which predispose the airways to RSV or OVA-induced epithelial apoptosis, injury, and other asthma responses.